This invention relates to the improvement of synthetic resins and particularly to the improvement in physical properties of both homopolymers such as polyalkylene (e.g. polyethylene) terephthalates, polyolefins, polyamides, polymethylmethacrylates, polysulfones, polyvinyl resins such as PVC and polystyrenes and copolymers such as the ABS family of plastic materials of which acrylonitrile-butadiene-styrene is a typical member and the thermoplastic elastomers, such as the styrene-butadiene or styrene-isoprene copolymers, this improvement resulting from the incorporation of a specialized class of inorganic crystalline materials as nucleating agents, into the polymer and the shaping of the polymer by extrusion or injection molding or other suitable techniques.
The properties and molding may be further improved by the addition of specialized materials which influence the crystallization of the polymer in a desired manner.
The use of nucleating agents to modify the crystalline structure of crystallizable polymers is known and is described in U.S. Pat. No. 3,367,926 (Vocks), U.S. Pat. No. 3,585,264 (Thomas) and in British Specifications 1,104,089 and 1,102,844 (both AKU) and elsewhere in the published literature. It has been found that the use of such agents is often unsatisfactory, especially when they are incorporated in polyalkylene terephthalates such as polyethylene terephthalates.
It has been further found that only when the nucleating agent is an inorganic crystalline nucleating agent with specific properties, is the desired improvement insured.